DistOS 2023W 2023-01-23

Discussion questions

Remember, these are just to get you started. Please allow your discussion to go where it will, so long as it is somewhat related to the readings.

• How distributed was the Mother of All Demos?
• How distributed was the Alto?
• How did the demo actually work? What was the system capable of?
• What could the Alto do? On what sort of hardware?
• How do these systems relate to the topics of this class?
• What did you find interesting? Surprising?
• Are there any ideas here that seem promising but we've "forgotten" about?

Notes

Lecture 5
---------

Significance of MOAD?
 - really was a glimpse of the future, blew people there away
 - *so* far ahead

But how real was it?
 - how much of it was on the computers?
    - video/audio? NO, was closed-circuit cameras/audio
    - graphics was overlays, not from the computer
 - how distributed was the computer part?
    - all running on one computer
    - communication was over dedicated data links (courtesy of the phone network), just providing serial connections for keyboard & mouse
    - (text) video was remotely projected
 
Much of the development of the Internet was an attempt to reach the vision of MOAD
 - and note it envisioned a distributed system on which everyone worked and
   could share data, and that would require distributed OS services

So what was the Alto, in relation to the MOAD?
 - people from Englebart's lab ended up at Xerox PARC

Technologies invented at Xerox PARC
 - ethernet
 - laser printers
 - GUIs
 - smalltalk (not first, but groundbreaking object-oriented programming)

Windows & Macintosh (well, the Lisa) were inspired directly by the Alto
 - note the original Mac didn't really do networking, didn't seem like such a big deal relative to GUIs and laser printers (desktop publishing)

Did they have a "distributed OS" at Xerox PARC? No, but they saw the benefit in trying to get networked computers to work together as "one system"
 - print servers
 - file servers
 - whole idea of "workgroup computing", where every individual would
   have their own computer but those computers could share network resources

The idea of having most of a computer's resources devoted to making an interface was revolutionary and controversial


Objective-C is Smalltalk + C
 - used by NeXT, formed basis of MacOS X

The Alto, and the tech developed at PARC, showed the possibility of personal computers when they were connected to a network.
 - Distributed OSs are an extension of that vision
 - collaboration & personal empowerment

The thing about a "bicycle for the mind" is that it assumes you know how to ride a bicycle
 - that requires training
 - the systems that succeeded in the marketplace required almost
   no training initially, could be used in a basic way very quickly
   (or seemed like they could)

This effort to make things "easy to use" isn't just for end users, it also applies to developers
 - we often want to be able to use systems immediately without investing
   any time learning new ways of doing things
 - developers are just as much like this as are regular users
 - Distributed OS started off trying to make things "easy to use",
   be just like what developers knew already (UNIX)
 - only later did they do things differently in order to maximize the power
   of the system